CVE-2026-6643 A stack-based buffer overflow vulnerability in the VPN Clients on the ADM

High 8.6 Published 20 Apr 2026 Updated 20 Apr 2026

An authenticated remote attacker can execute arbitrary code via a stack-based buffer overflow in ASUSTOR ADM VPN clients.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-6643?

CVE-2026-6643 is a high-severity memory corruption vulnerability in ASUSTOR Inc. ADM, published on 20 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

A stack-based buffer overflow vulnerability was found in the VPN Clients on the ADM. The issue stems from the use of unbounded sscanf() and passing user-controlled data directly to printf(). Due to the lack of PIE and Stack Canary protections, an authenticated remote attacker can exploit these to execute arbitrary code as the web server user. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RR42 as well as from ADM 5.0.0 through ADM 5.1.2.REO1.

Weakness: CWE-121

Which versions are affected by CVE-2026-6643?

It affects 1 product.

Products include Asustor Data Master.

How do I fix CVE-2026-6643?

No fix has been published for CVE-2026-6643 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-6643 being exploited?

There is no known exploitation of CVE-2026-6643 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Sources

Also known as GHSA-46vm-f48w-xhvv.